Verifiable object having incremental key

ABSTRACT

An object verification system generates an incremental verification key which can be carried on the object co-extensive with the region of the associated randomly varying characteristic. The incremental key can be formed by measuring values of the characteristic and comparing selected pairs of values. The algebraic sign of the comparison can be used as an indicium for creating a verification key distributable across the region of the object. Alternately, the magnitude of the difference between the selected pairs of values can be also be included in some or all of the indicia.

This is a continuation-in-part of Copella Pat. Applic. Ser. No. 361,946filed June 5, 1989 now U.S. Pat. No. 4,985,614 entitled "ObjectVerification Apparatus and Method" and incorporated herein by reference.

FIELD OF THE INVENTION

The invention pertains to objects whose authenticity can be verified.More particularly, the invention pertains to both documents and othertypes of objects which carry a magnetic region. The magnetic region canbe used to verify the authenticity of the document or other object.

BACKGROUND OF THE INVENTION

Problems associated with the forgery or counterfeiting of various typesof documents are long standing and well known. For example, forgery oftransportation tickets, negotiable instruments, currency or otherdocuments of value is a continuing and ongoing problem to issuers ofsuch documents.

The widespread use of plastic credit or debit cards has created, yet,another set of authentication and verification problems. It is verycommon for such cards to include pre-recorded magnetic stripes whichinclude transaction related information. This information can includeaccount numbers, credit limits and/or personal identification codes.

However, such cards have been especially susceptible to forgery in viewof the fact that the magnetic encoding is almost always based on one ormore publicly known standards. One such standard, ANSI 4.16-1983 isutilized in connection with many pre-recorded magnetic stripesassociated with such cards.

Multi-use transportation documents present yet another type ofauthentication problem. Such documents are magnetically alterable at thetime of use to decrease the remaining value of the card. However, if anoriginal, unused document can be both physically and magneticallyduplicated to create a useable counterfeit document, the issuing agencycan loose substantial proceeds.

Various systems are known which can be utilized to create andauthenticate verifiable documents or credit cards. Some of the knownsystems are magnetically based. Other are optically based.

One known type of system is disclosed in U.S. Pat. No. 4,837,426 toPease et al. entitled "Object Verification Apparatus And Method" whichis assigned to the Assignee of the present invention. The disclosure andfigures of the Pease et al. patent are hereby incorporated herein byreference.

In the system of the Pease et al. patent, a randomly varying magneticcharacter is measured and used to create a verification key which can becarried on the document. The verification key of the Pease et al. systemis a result of processing sensed values of the random magneticcharacteristic and creating a single key for the entire document.

A different magnetically based security system is disclosed in U.S. Pat.No. 4,806,740 to Gold et al. entitled "Magnetic CharacteristicIdentification System". As in the case of the Pease et al. system, thesystem of the Gold et al. patent creates a verification key for thedocument which can be carried thereon.

Optically based security systems are disclosed in U.S. Pat. No.4,423,415 to Goldman entitled "Noncounterfeitable Document System". Inone embodiment disclosed in the Goldman system, the translucency of aregion of a document is utilized as the measured randomly varyingcharacteristic. Alternately, the Goldman patent also discloses the useof reflectivity for the same purpose. Whether translucency orreflectance are utilized, the system of the Goldman patent also createsa single verification key for a given document.

While known systems appear to be effective with respect to verificationof certain types of objects, in each instance, the verification keycreated for an object is the result of processing measuredcharacteristic values over a region of the object. From these measuredand processed characteristic values, a verification key is generated forthe entire region and hence the object.

There are times where it would be desirable to be able to verify theauthenticity of only a portion of the object. The known systems, need tohave the entire region of the random characteristic available. As aresult, the known systems are unable to determine if a portion of adocument is in fact authentic.

Hence, there continues to be a need for authentication/verificationsystems of more general applicability then has previously been known.Preferably, such systems would be usable to properly authenticate aportion of an object. In addition, preferably such systems would bereadily usable with magnetically based randomly varying characteristicsas well as optically based characteristics.

SUMMARY OF THE INVENTION

Methods and devices are provided for creating and verifying objectsutilizing a randomly varying characteristic carried thereon. Thecharacteristic itself can take a variety of forms. It may be magnetic,it may be the translucency of a region of the object or alternately,reflectivity of a region of the object.

The values of a parameter of the random characteristic are sensed. Thesensed values are then processed.

The processing involves comparing or subtracting pairs of parametervalues and determining an algebraic sign of the result. If the sign ispositive, for example, an indicium thereof can be recorded on theobject. Negative signs need not be recorded.

The process can then be repeated for the next pair of parameter valuesuntil the region of the randomly variable characteristic ends. Thisprocess forms an incremental or distributed key.

The various indicia can be recorded on the object, at or about the timeof the processing step. Thus, when the end of the region of the randomcharacteristic has been reached, the object carries a plurality ofspaced-apart indicia which represent an incremental profile thereof.

One of the important advantages of the above-described incrementalverification profile is that it can be used to verify the authenticityof a portion of an object. This profile or key is carried along a regionof the object which can be coextensive with the region of the randomlyvariable characteristic of the object.

If the object is torn into two pieces such that both pieces carry a partof the random characteristic and a part of the incremental verificationkey then one or both of those pieces can be verified using the portionof the region and the key carried thereon.

As an alternate to merely recording the algebraic sign of the results ofa comparison or difference between the two parameter values, an indiciumof the magnitude of that difference can also be recorded along with thesign. This provides a more complex incremental verification key with aresultant higher level of security.

The magnitude of the difference can be encrypted before being recordedon the document. Alternately, the key can be stored, not on the object,but at a remote location.

An apparatus for validating an object which carries an incrementalverification key includes a reader or sensor for sensing the values of aparameter of the random characteristic. As these values are sensed,differences between pairs of values are formed. The result of thedifference can be a magnitude along with an algebraic sign or only thealgebraic sign by itself.

Simultaneously, the indicia corresponding to the incremental key arealso being sensed or read off of the object by a suitable sensor orreader. The apparatus also includes control circuitry for comparing thenewly formed incremental indicium with the corresponding incrementalindicium read off of the object.

When the end of the randomly variable characteristic has been reached,the apparatus will contain a number corresponding to the number ofmatches which have been detected between the newly created incrementalverification key and the corresponding indicia carried on the object.The apparatus will also contain the total number of newly formedelements of the verification key which have resulted from the mostrecent pass of the document over the read heads or sensors.

The ratio of these two numbers is a measure of the authenticity of thedocument. For a perfect document, the value of this ratio should be one.For real documents, the value may be a decimal less than one. Byestablishing a threshold, the required number of matches to arrive adecision that the document is authentic can be increased or decreased.

In one embodiment of the invention, the random characteristic can bethat of a magnetic region carried by the object. To enhance thereadability or detectability of values of the random characteristic ofthe magnetic region, a discontinuous electrical signal can be saturationrecorded thereon. For example, a square wave can be saturation recordedonto a part of the magnetic region.

The flux changes associated with the previously recorded square wavewhen passed through a readhead and converted to voltages can bemeasured. Peak values can be used, as described previously, to formpairs of amplitude values from which amplitude differences can beformed.

The amplitude differences can be formed using only positive goingpulses, for example. The negative going pulses can be used as clockpulses to determine where each incremental indicium, corresponding to adifference in a specific pair of amplitude values, should be recorded onthe object. The plurality of indicia can be recorded in a portion of thesame magnetic region or it can be printed on the object and readoptically.

In a similar fashion, a clock track can be created on a magnetic regionwhich is coextensive with a region of translucency or reflectivity ofthe object for the purpose of measuring an optically based randomcharacteristic.

Each of the incremental verification indicia can be recorded on theobject displaced from a respective base line an amount proportional tothe difference between the respective pair of values of the randomcharacteristic. The direction of displacement can identify whether thedifference has a positive or a negative sign.

In alternate embodiments, the random characteristic can be that oftranslucency or reflectance of a document or article. The particulartype of random characteristic is not a limitation of the invention.

Numerous other advantages and features of the present invention willbecome readily apparent from the following detailed description of theinvention and the embodiments thereof, from the claims and from theaccompanying drawings in which the details of the invention are fullyand completely disclosed as a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, enlarged, planar, schematic view of averifiable document usable with the present invention;

FIG. 2A is a graph illustrating electrical signals as a function of timeread from the profile track of the document of FIG. 1;

FIG. 2B is a schematic timing diagram illustrating recorded incrementalkey elements relative to down going pulses of the graph of FIG. 2a;

FIG. 3 is a block diagram schematic of a device for verifying a documentor a card with a magnetic security system in accordance with the presentinvention;

FIGS. 4A, 4B, and 4C taken together are a set of graphs illustratingwave forms generated by the verification apparatus of FIG. 3;

FIG. 5 is a flow diagram of a method of validation of a document or acard carrying a security system in accordance with the presentinvention;

FIG. 6 is a flow diagram of a method of encoding a document or a cardwith an incremental key in accordance with the present invention;

FIG. 7 is a block diagram schematic of a digital circuit for reading arandom characteristic off of a card or an object and comparing thatcharacteristic to a prewritten incremental key;

FIGS. 8A-8G taken together are graphs of a plurality of wave forms fromthe circuit of FIG. 7 as a function of time;

FIG. 9 is a schematic representation of an apparatus for encoding a cardor other object; and

FIGS. 10A-10C taken together are a flow diagram illustrating a method ofoperation of the apparatus of FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While this invention is susceptible of embodiment in many differentforms, there is shown in the drawing and will be described herein indetail a specific embodiment thereof with the understanding that thepresent disclosure is to be considered as an exemplification of theprinciples of the invention and is not intended to limit the inventionto the specific embodiment illustrated.

FIG. 1 schematically illustrates a portion of a planar object ordocument 10 which carries one or more magnetic tracks thereon 12, 14,16a and 16b. Tracks 12 and 14 can be of a type commonly used withmagnetically readable and writable documents or cards as are currentlyknown and in general use.

Tracks 16a and 16b, which could be combined together in a single track,represent security tracks which are written onto and read back from inaccordance with the present invention. Tracks 16a and 16b are notrecorded in standard commercial format.

Track 16a is used to read a unique random magnetic prifle of thedocument 10. Track 16a is saturation recorded with a square wave at adensity on the order of 420 transitions per inch as the object 10 movespast a magnetic write head. Track 16b is used to store an incrementaldigital or analog representation or key for the sensed profile fromtrack 16a.

FIG. 2A is a graph illustrating an electrical signal which can be readback off of track 16a in response to the saturation recorded squarewave. Each of the transitions, such as transitions 20a or 20b representeither a positive going or a negative going transition respectively ofthe original electrical square wave which was saturation recorded ontotrack 16a.

The principles of the present magnetic security system are illustratedin FIG. 2A. The peak value of transition 20a is compared to the peakvalue of a subsequent positive going transition 20c. Because of theknown variations in magnetic stripes, no matter how carefully thestripes are created, the peak value of transition 20a will not be thesame as the peak value of transition 20c. As illustrated in FIG. 2A, thepeak value of transition 20c is greater than the peak value oftransition 20a.

Similarly, if transition 20c is compared to transition 20d, asillustrated in FIG. 2A, the peak value of transition 20d issubstantially less than the peak value of transition 20c. Similarly, thedifferences to subsequently sensed pairs of, peak values, such as pairs20d, 20e; 20e, 20f; and 20f, 20g are considered.

In one embodiment of the present invention the sign and the magnitude ofthe relative differences in peak value for a given pair of positivetransitions can be recorded onto key track 16b, as an incrementalrepresentation of the profile on track 16a, as illustrated in FIG. 2B.The negative going transitions recorded and read back from the profiletrack 16a, such as negative going transition 20b, can be used to clockthe information read back from the key track 16b.

For example, marker bits 22a through 22e can be recorded onto the keytrack 16b with a phase relationship relative to an adjacent negativegoing transition, such as transition 20h. These bits can be recordedwith a sign and a value directly proportional to the difference inadjacent peak values such as the positive going pairs of peak values 20aand 20c.

With respect to FIG. 2B, incremental encoded key element 22a has beenencoded onto track 16b with a phase which leads or is in advance ofnegative going pulse 20h. Similarly, recorded key element 22b which isindicative of a negative going incremental change between the peakvalues of pulses 20c and 20d has been recorded on the encode track 16bwith a negative or lagging phase with respect to negative going pulse20i.

Other incremental key elements 22c, 22d, and 22e have been recorded onencode track 16b with a phase and displacement relative to associateddown going pulses 20j, 20k, 201, similarly.

It will be understood that an incremental key can be recorded on keytrack 16b in several alternate ways. For example, only positive goingamplitude changes for a given pulse pair which exceed a predeterminedthreshold need be recorded. Alternately, only negative going amplitudechanges that exceed a given threshold need be recorded.

FIG. 3 illustrates schematically a system 30 for reading secured objectssuch as the object 10 and comparing a newly read profile, off of track16a, to the recorded and encoded profile on track 16b. The system 30includes read heads 32a and 32b which are aligned and function to readthe information on the tracks 16a and 16b.

Read heads 32a and 32b are each electrically coupled to analog phasedetector 34. The read head 32a which reads the profile track is alsoelectrically coupled to analog profile detector 36.

The analog outputs from the phase detector 34 and the profile detector36 are both coupled as inputs to differential amplifier 38. Output fromthe differential amplifier 38, the difference between the analog signalsfrom the phase detector 34 and the profile detector 36, is coupled tocomparator 40.

A second input to comparator 40 is a sensitivity or a threshold inputfrom element 42. The comparator 40 compares the difference signal fromdifferential amplifier 38 to the adjustable threshold from element 42.

If the magnitude and the phase of the prerecorded key element, such asthe element 22a, corresponds to the magnitude and sign of the differencein peak amplitudes between corresponding transitions 20a and 20c, a truesignal is generated by comparator 40. In the event of a differencebetween the newly read profile off of track 16a and the pre-recordedencoded profile from track 16b, the comparator generates a false orerror signal as in output.

The element 42 provides a way to adjust the sensitivity of the device30.

FIG. 4 is a plurality of graphs which illustrates some of the electricalsignals associated with the device 30. FIG. 4A is a graph of an outputfrom profile detector 36 is illustrated in response to profile track 16abeing read. As illustrated in FIG. 4A, the output from profile detector36 is an analog output with a sign and magnitude proportional to thedifferences in peak magnitude of pairs of positive going pulses such aspulses 20a and 20c.

FIG. 4B is a graph of the electrical signals generated by phase detector34 which also generates an analog output. Finally, FIG. 4C is a graph ofelectrical signals generated by phase detector 34 on an output datavalid line 44. The data valid strobe on the line 44 indicates timeintervals when the output signal on line 40a can be sensed.

Thus, the apparatus 30 detects the characteristics of the profile track16a and compares same to the incremental key recorded on the track 16bmaking it possible to easily and quickly verify the authenticity of thedocument or card 10. One particular advantage of the process illustratedin FIG. 2 and the apparatus of FIG. 3 is that a document or card can beauthenticated by only reading a portion of the profile track and aportion of the key track. It is unnecessary to read the entire profiletrack or the entire key track.

FIG. 5 illustrates a flow diagram of the validate process as previouslydescribed with respect to the apparatus 30. In a step 50 a firstpositive going peak value, such as the peak value of the pulse 20a, issensed and stored. In a step 52 the peak value of a second positivegoing pulse, such as the pulse 20c, is sensed and stored.

In a step 54 the first and second previously read and stored peak valuesare subtracted from one another. In a step 56 a negative going pulse,such as the pulse 20h, is detected.

In a step 58 a key element, such as key element 22a or 22b, is detectedand the sign of the phase of that element relative to the respectivenegative going pulse, such as pulse 20h, is compared to the previouslyset mask indicating the sign of the difference between peak values ofadjacent pulses such as pulses 20a and 20c. In a step 60 the signal onthe data valid line is set and an appropriate output is generated on thecompare output line 40a.

Finally, in step 62 the previously read second peak positive goingvalue, such as the pulse 20c, is moved in to the first storage locationand the process repeats.

FIG. 6 illustrates the steps of a process for encoding incremental keyelements onto the track 16b in response to reading the profile track16a.

While the system 30 and related method have been disclosed and describedin connection with a randomly varying magnetic security system, theprinciples hereof are applicable to other types of randomly varyingsecurity characteristics. For example, other applicable types of regionsinclude translucency or reflectance variations of documents. Stillothers include random variations in print locations or thicknessprofiles of documents.

FIG. 7 illustrates an alternate, digital, system 70 usable to readprofile tracks of the type 16a, as well as incremental key tracks suchas the track 16b and generate a validity indication for thecorresponding document. The system 70 includes readheads 72 and 74 forrespectively sensing the random characteristic of the profile track 16aas well as the prerecorded incremental key track 16b. Outputs from eachof the readheads 72 and 74 are respectively coupled to operationalamplifiers 72a and 74a.

Output from the amplifier 72a, on a line 72b, is a representation of thesensed random magnetic characteristic of the profile track 16a. Agraphical representation of the amplified signal on the line 72b isillustrated in FIG. 8A as a functional time. Output from the amplifier74a, on a line 74b, a representation of the prerecorded incremental keyfrom the track 16b is illustrated in FIG. 8D as a function of time.

Profile signals on the line 72b are coupled to peak detect circuitry 76.Output from peak detect circuitry 76 on lines 76a and 76b representspeak values of pairs of positive going profile signals such as thesignals 78a and 78b of FIG. 8a. Output on the line 78a is temporarilystored in sample and hold amplifier 80a. Output on the line 76b istemporarily stored in and hold amplifier 80b.

The peak value from pulse 78a, from amplifier 80a is subtracted frompeak value of pulse 78b held in amplifier 80b in an adder 82. Thedifference between from amplifiers 80a and 80b is compared in acomparator 84 to an adjustable threshold to determine whether or not thedifference exceeds a preset minimum. Output from comparator 84 on a line84a is illustrated in graphical form in graph FIG. 8F.

Subsequent to comparing the pair of peak values for the signal 78a and78b, the peak detect circuitry 76 in combination with sequence controllogic 86 then compares the pair of peak pulse values corresponding tothe pulses 78b and 78c.

All subsequent pairs of pulses on the profile rack 16a are sensedaccordingly.

Signals representative of the incremental key indicators recorded on thetrack 16b, on the line 74b, provide inputs to key detect circuitry 86.Output from key detect circuitry 86 on the line 86a corresponds to apositive going pulse in the presence of a sensed, prerecorded, keysymbol as illustrated in the graph of FIG. 8e.

Clock recovery circuitry 88 generates a comparison window positive goingsignal on a line 88a as illustrated in the graph of FIG. 8C in responseto negative going edges of the profile track signals on the line 72b.Clock recovery circuitry 88 also generates positive going data strobepulses on a line 88b corresponding to the pulse train of FIG. 8B.

The signals on the lines 84a, 88a and 88b provide inputs to the Key andProfile Compare circuitry 90. Key and Profile Compare circuitry 90generates a zero on an output line 90a as represented by the wave formof the graph of FIG. 8G where the comparison between the most recentlyread pair of signals off of the profile track differs from the signalread off of the incremental key track of FIG. 16b. The data valid strobeoutput on the line 88b is usable for purposes of strobing the output onthe line 90a.

FIG. 9 illustrates schematically an apparatus 100 for reading profiletracks, such as the track 16a and then generating and writingincremental key representations on the track 16b. The flow diagram ofFIGS. 10A, 10B and 10C taken together depict a method of reading theprofile track off of a card, such as the card 102 and writing onto theincremental key track thereof using the apparatus 100.

In a step 110, the card 102 to be encoded, enters station A and iserased. The card 102 then enters station B in a step 112 and the profiletrack is written with a predetermined random characteristic enhancingelectrical signal, such as a saturation recorded square wave.

The card 102 then enters station C in a step 114 and the enhanced randommagnetic characteristic of the profile track, such as the track 16a, isread or captured by one or more read heads. In a step 114a, the recordedanalog signatures sensed by a plurality of parallel heads are averaged.

In a step 116, the card 102 enters the write station D and theincremental key, based on having read the entire profile track, isgenerated and written onto the key track.

FIG. 10B represents the steps of the apparatus of station D in writingthe incremental key onto the key track such as the key track 16b. In astep 118, the representation of the incremental key to be written issynchronized with a negative going transmission off of the profiletrack. If the key bit is a logical one a representation thereof aswritten onto the key track in a step 120.

In a step 122, the next generated bit of the incremental key isretrieved from storage and the process of step 118 is repeated. When theend of key data is sensed in a step 124, the card 102 then entersverified station E of the apparatus 100.

The flow diagram of FIG. 10C illustrates the steps in a method executedby the apparatus of station E to verify that the key which has beenwritten onto the card 102 corresponds to the sensed profile in a step126. If the recorded key does not match the newly read profile, assensed in a step 128, to an extent which exceeds a predeterminedthreshold, the card is rejected in a step 130. If the newly sensedprofile patches the prerecorded key to an extent exceeding theprerecorded threshold, the card is accepted in a step 132 and theprocess is re-initiated in a step 134 with a new card.

The above described digital system and method are also usable, withappropriate sensors, with a variable translucence or reflectance opticalsecurity system. It is also usable with other types of randomly variablecharacteristics.

From the foregoing, it will be observed that numerous variations andmodifications may be effected without departing from the spirit andscope of the novel concept of the invention. It is to be understood thatno limitation with respect to the specific apparatus illustrated hereinis intended or should be inferred. It is, of course, intended to coverby the appended claims all such modifications as fall within the scopeof the claims.

We claim:
 1. A method of creating an incremental security profile of arandomly varying characteristic of an object comprising:(a) sensingfirst and second values of a parameter of the characteristic; (b)generating an incremental indicium indicative of a difference betweenonly the two values; (c) recording the incremental indicium; andrepeating steps (a)-(c).
 2. A method as in claim 1 with the generatingstep including forming an indicium that includes an algebraic sign ofthe difference.
 3. A method as in claim 1 including generating aplurality of indicia with at least some of the indicia including both analgebraic sign and a representation of a difference between only tworespective random characteristic values.
 4. A method as in claim 1including, in step (c), writing a representation of the incrementalindicium onto the object.
 5. A method as in claim 1 including writing aplurality of representations of incremental indicia onto the object. 6.A method as in claim 1 including, in step (c), forming a displacementrelated representation of the indicium prior to recording.
 7. A methodas in claim 1 with the randomly varying characteristic that of amagnetic region and including writing a characteristic enhancingdiscontinuous digital signal onto the magnetic region.
 8. A method as inclaim 7 with step (c) including writing the incremental indicia onto aportion of the magnetic region.
 9. A method as in claim 7 with step (c)including writing the incremental indicia onto the object.
 10. A methodas in claim 7 with step (c) including storing the indicia at a locationremote from the object.
 11. A method as in claim 1 with the randomlyvarying characteristic the translucency of a portion of the object. 12.A method as in claim 1 with the randomly varying characteristic thereflectance of a portion of the object.
 13. A method as in claim 1 withthe sensed parameter values corresponding to amplitudes representativeof the random characteristic and with the generated indicium of step (b)including an algebraic sign of a difference between first and secondamplitude values.
 14. A method as in claim 13 with the generatedindicium including in addition a representation of the amplitudedifference.
 15. A method as in claim 1 with the indicium recorded onlywhen corresponding to a selected algebraic sign.
 16. A method as inclaim 1 with the generated indicium recorded on the object as adisplacement relative to a respective base line.
 17. An apparatus forcreation of an incremental profile of a randomly varying verificationcharacteristic of an object comprising:means for sensing values of aselected parameter of the characteristic; means for sequentiallycreating a plurality of indicia with each indicium representative of anincremental difference between selected first and second values of theparameter of the characteristic; and means for recording some of saidindicia after creation.
 18. An apparatus as in claim 17 with theverification characteristic carried by a magnetic region on the objectand wherein said sensing means includes means for reading the magneticregion.
 19. An apparatus as in claim 17 with the verificationcharacteristic carried in a translucent region of the object and withthe apparatus including means for detecting translucency of the region.20. An apparatus as in claim 17 including means, coupled to saidrecording means, for selecting those indicia to be recorded.
 21. Anapparatus as in claim 20 with each said indicium including at least arepresentation of an algebraic sign representative of said incrementaldifference and with said selecting means including means for enablingrecording of only indicia corresponding to a selected algebraic sign.22. An apparatus as in claim 17 with said recording means includingmeans for generating displacements relative to a base line with saiddisplacement representative of respective ones of said series ofindicia.
 23. An apparatus as in claim 22 including means for writingrepresentations of at least selected of said displacements onto theobject.
 24. An apparatus as in claim 23 with said writing meansincluding a printer.
 25. An apparatus as in claim 23 with said writingmeans including a magnetic write head.
 26. An apparatus as in claim 17with said creating means including means for forming an amplitudedifference between first and second values of the parameter.
 27. Averifiable object comprising:a base; a unique, randomly variablemeasurable characteristic carried by said base; a relative, incrementalrepresentation of said characteristic extending along said base as aplurality of spaced apart indicia with each said indicium including arepresentation of a difference between selected first and second valuesof a parameter of said characteristic.
 28. A verifiable object as inclaim 27 with at least some of said indicia including a representationof an algebraic sign of said difference.
 29. A verifiable object as inclaim 28 with said indicia including a representation of only analgebraic sign.
 30. A verifiable object as in claim 27 with at leastsome of said indicia including a value corresponding to a differencebetween first and second amplitude values of said characteristic.
 31. Averifiable object as in claim 27 including a magnetic region on saidbase, said magnetic region including said randomly variable, measurablecharacteristic.
 32. A verifiable object as in claim 27 including aradiant energy transmissive region on said base with said transmissiveregion including said randomly variable, measurable characteristic. 33.A verifiable object as in claim 27 including a region, at least in partreflective of radiant energy, on said base with said reflective regionincluding said randomly variable, measurable characteristic.
 34. Averifiable object as in claim 27 including a recordable magnetic regionwith said spacedapart indicia recorded thereon.
 35. A verifiable objectas in claim 27 with representations of said spaced apart indicia printedthereon.
 36. A verifiable object as in claim 27 including means forenhancing said measurable characteristic.
 37. A verifiable object as inclaim 31 including a predetermined characteristic enhancing electricalsignal written onto said magnetic region.
 38. A verifiable object as inclaim 37 with said enhancing electrical signal a saturation recorded,discontinuous, multi-valued signal.
 39. A verifiable object as in claim27 with each said indicium carried on said base as a machine readabledisplacement relative to a respective base line.
 40. A verifiable objectas in claim 27 with each said parameter value corresponding to anamplitude value of said randoml variable characteristic.
 41. Averifiable object as in claim 40 with at least some of said indiciaincluding an algebraic sign of a corresponding amplitude difference. 42.An object which carries an incremental verification key usable forverification of an available part of the object, the object comprising:abase; a unique, randomly variable measurable characteristic extendingalong a region of and carried by said base; an incremental, distributed,verification key extending along a second region of and carried by saidbase with a subset of said key, contained within the part of the objectand combinable with an associated subsection of said region forverification of the part of the object.
 43. An object as in claim 42with said key including a plurality of indicia distributed in saidsecond region with each said indicium including a representation of adifference between first and second values of a parameter of saidcharacteristic.
 44. An object as in claim 42 with a magnetic regioncarried on said base with said magnetic region containing said randomlyvariable characteristic.
 45. An object as in claim 44 with said magneticregion being at least in part, recordable.
 46. An object as in claim 42with a magnetic region carried on said base and with said second regioncontained therein.
 47. An object as in claim 46 with said randomlyvariable characteristic contained in said magnetic region.
 48. An objectas in claim 42 with a translucent region carried on said base andcontaining said randomly variable characteristic.
 49. An object as inclaim 42 with a reflective region carried on said base and containingsaid randomly variable characteristic.
 50. An object as in claim 43 withsaid representation carried by said base as a displacement with respectto a selected reference.
 51. An object as in claim 42 with saidmeasurable characteristic extending in an arcuate region.
 52. An objectwhich carries a distributed verification key with a subpart of theobject carrying a subset of the verification key, the subpart beingindependently verifiable, the object comprising:a base; a uniquerandomly variable measurable characteristic extending along a region ofand carried by said base with a part of said region extending into asubpart of said base; and a distributed verification key formed of aplurality of indicia extending along a second region, extensive withsaid region, carried by said base with a portion of said pluralitycontained within said subpart of said base, said part of said regionbeing detectable and combinable with said portion of said plurality forverification of the subpart of the object.
 53. An object as in claim 52with each said indicium including a representation of a differencebetween first and second values of a parameter of said characteristic.54. An object as in claim 53 with each said parameter value an amplitudevalue of said random characteristic.
 55. An object as in claim 52 withat least some of said indicia including an algebraic sign of anamplitude difference between first and second amplitude values of saidrandom characteristic.
 56. An object as in claim 52 with a magneticregion carried on said base with said magnetic region containing saidrandomly variable characteristic.
 57. An object as in claim 56 with saidmagnetic region being at least in part, recordable.
 58. An object as inclaim 52 with a magnetic region carried on said base and with saidsecond region contained therein.
 59. An object as in claim 58 with saidrandomly variable characteristic contained in said magnetic region. 60.An object as in claim 52 with said second region extending substantiallyequidistant from said region.
 61. An object as in claim 52 with saidverification key extending in a curved region.
 62. An apparatus forvalidating an object which carries a unique, randomly variablemeasurable characteristic which extends along a region thereof and whichalso carries an incremental verification key, formed of a plurality ofspaced apart indicia, which extends along a second region thereof, theapparatus comprising:a first sensor for detecting peak values of saidrandomly variable characteristic; circuitry for processing pairs of thedetected peak values; a second sensor for detecting at least some ofsaid indicia; circuitry for comparing processed, detected, pairs of peakvalues to corresponding of said indicia; and circuitry for generating avalidity indicium in response to said comparison.
 63. An apparatus as inclaim 62 with said processing circuitry including means for formingdifferences between pairs of detected peak values.
 64. An apparatus asin claim 63 including further means for forming a plurality of algebraicsigns with each sign associated with a respective formed difference. 65.An apparatus as in claim 62 with said second detecting sensor includingmeans for sensing displacement relative to a respective reference. 66.An apparatus as in claim 62 with the randomly variable characteristicextending in a curved region and with said first sensor operative alongsaid curved region.
 67. A method of validating an object which carries aunique, randomly variable, measurable characteristic which extends alonga region thereof and which also carries an incremental verification keyformed of a plurality of spaced apart indicia which indicia extend alonga second region thereof, the method comprising:detecting peak amplitudevalues of the randomly variable characteristic; processing the detectedpeak amplitude values; detecting displacement relationships between someof the verification indicia and respective base indicators associatedtherewith; comparing the processed, detected peak amplitude values tocorresponding of the displacement relationships; and generating avalidity indicium in response to said comparison.
 68. A method as inclaim 67 with the processing step including forming a difference betweenfirst and second peak amplitude values.
 69. A method as in claim 67 withthe processing step including forming an algebraic sign of a differencebetween first and second peak amplitude values.
 70. A method of creatingan incremental profile of a randomly varying characteristic of an objectcomprising:(a) sensing first and second amplitude values of a parameterof the characteristic; (b) generating an incremental indicium based on adifference between amplitudes of only the two values; (c) recording theincremental indicium; and repeating steps (a)-(c).
 71. A method as inclaim 70 with the generating step including forming an indicium with analgebraic sign of the difference.
 72. A method as in claim 70 includinggenerating a plurality of indicia with at least some of said indiciaincluding both an algebraic sign and a representation of an amplitudedifference between only two respective random characteristic values. 73.An apparatus for creation of an incremental profile of a randomlyvarying verification characteristic of an object comprising:means forsensing amplitude values of a selected parameter of the characteristic;means for sequentially creating a series of indicia with each indiciumrepresentative of a difference between respective first and secondamplitude values of the characteristic; and means for recording eachsaid indicium on the object.
 74. An apparatus for validating an objectwhich carries a unique, randomly variable measurable characteristicwhich extends along a region thereof and which also carries anincremental verification key, formed of a plurality of spaced apartindicia, which extends along a second region thereof, the apparatuscomprising:a first sensor for detecting peak values the randomlyvariable characteristic; a device for processing the detected peakvalues; a second sensor for detecting relationships between some of theindicia and a respective reference; a comparator for comparingprocessed, detected, peak values to corresponding of said detectedrelationships; and an indicator for generating a validity indicium inresponse to said comparison.
 75. An apparatus as in claim 74 with saidprocessing device including an arithmetic unit for forming differencesbetween pairs of detected pea values.
 76. An apparatus as in claim 75including circuitry for forming a plurality of algebraic signs with eachsign associated with a respective formed difference.
 77. An apparatus asin claim 74 with said second sensor including means for sensingdisplacement relative to the respective reference.
 78. An apparatus asin claim 74 with the randomly variable characteristic extending in acurved region and with said first sensor operative along said curvedregion.
 79. An apparatus as in claim 74 with said first sensor includinga magnetic read head.
 80. An apparatus as in claim 74 with said secondsensor including an optical detector.
 81. An apparatus as in claim 74with said processing device including a programmed computer.
 82. Anapparatus as in claim 81 with said programmed computer including saidcomparator.
 83. An apparatus as in claim 81 with said programmedcomputer including said validity indicium generating indicator.
 84. Anapparatus as in claim 81 with said programmed computer including anarithmetic unit for forming differences between pairs of detected peakvalues.